Communications networks generally transmit data at a high frequency over cables having a plurality of twisted signal pairs of conductors. For example, according to currently accepted performance standards, Category 5 products operate at frequencies up to 100 MHz and Category 6 products operate at frequencies up to 250 MHz over Unshielded Twisted Pair (UTP) cable that contains eight (8) individual conductors arranged as four (4) twist pairs. When data is transmitted via an alternating current in a typical telecommunication application at such high frequencies, each individual conductor and each signal pair creates an electromagnetic field that can interfere with signals on adjacent conductors and adjacent signal pairs. This undesirable coupling of electromagnetic energy between adjacent conductor pairs, referred to as crosstalk, causes many communications problems in networks.
Crosstalk is effectively controlled within communication cables through the use of twisted pairs of conductors. Twisting a signal pair of conductors causes the electromagnetic fields around the wires to cancel out, leaving virtually no external field to transmit signals to nearby cable pairs. In contrast, Near End Crosstalk (NEXT), the crosstalk that occurs when connectors are attached to twisted pair cables, is much more difficult to control. Since twisted signal pairs must be untwisted into individual conductors in order to attach a connector, high levels of NEXT are introduced when portions of transmitted signals within the connector are electromagnetically coupled back into received signals.
In efforts to control NEXT, a wide variety of modular plugs have been developed for terminating communications cables that contain twisted signal pairs of conductors. As communication technology advances, however, and allows transmission at higher and higher frequencies, the modular plugs known in the prior art are no longer capable of maintaining NEXT levels within the ranges specified in widely accepted national performance standards. For Category 6 products, for example, the Commercial Building Telecommunications Wiring Standard (ANSI/TIA/EIA-568) specifies a de-embedded NEXT test plug range which all patch cord plugs should meet to ensure interoperable Cat 6 performance. In order to satisfy TIA/EIA 568B-2.1, patch cord plugs must be designed with low NEXT variability centered within the specified de-embedded NEXT test plug range. In standard plug designs, however, pair-to-pair distortion, twist rate, and individual conductor positions are not strictly controlled. Hence, large variations of NEXT performance occur. Prior art modular plug designs also cause increased de-embedded NEXT variability by utilizing strain relief components that consist of a latching bar that pinches the cable jacket, prohibiting cable movement within the plug housing. In order to generate sufficient retention force, these bar style strain relief components significantly deform the cable jacket and the twisted pair conductors within the jacket. This pinching deformation causes distortion and displacement of twisted pairs of conductors that in turn causes increased de-embedded NEXT variability.
Accordingly, there is a demand for an improved modular cable termination plug.